A calcium looping process for simultaneous CO2 capture and peak shaving in a coal-fired power plant

Abstract

CO2 capture and peak shaving are two of the main challenges for coal-fired power plants in China. This paper proposed a calcium looping (CaL) combustion system with cryogenic O2 storage for simultaneous flue gas decarbonization and peak shaving for a 1000 MWe coal-fired power plant. The philosophy of this concept is that: 1) the boiler always operates at maximum continuous rating (MCR) to ensure the highest boiler efficiency; 2) during off-peak times, the excess energy output from coal combustion is used to provide heat for the calciner and produce pure oxygen for energy storage; 3) at peak times, the O2 produced is used to capture CO2 in the flue gas via the CaL process and reduce the CO2 abatement penalty; and 4) any excess O2 is treated as a by-product for commercial utilization. The whole system was simulated in Aspen Plus ® which shows that the net electric efficiency of the proposed system without cryogenic O2 storage system is 35.52%LHV (LHV, low heating value), while that of the conventional CaL system is 34.54%LHV. The proposed system can reduce the methane consumption rate by 38.5 t/h when methane is used as fuel in the calciner. Including the cryogenic O2 storage system, the peaking capability of the proposed system can range from 534.6

A study of the synergistic effects of Mn/steam on CO2 capture performance of CaO by experiment and DFT calculation

“…(b) and (c), a shift to the highest binding energy of Ca 2p and O 1s in C‐Mn‐CaO was found, which was not observed in the original CaO. It means that it was easier for the Ca atom and O atom in C‐Mn‐CaO to give electrons to CO 2 than the original CaO, which assisted the fast formation of CO 3 . The doping of Mn in CaO was beneficial to the electron transport from CaO to CO 2 , which accelerated the carbonation rates of CaO.…”

“…Among the CO 2 emission‐reduction technologies, calcium looping technology, i.e. carbonation/calcination cycles of CaO, is regarded as one of the most promising technologies for large‐scale CO 2 capture owing to its low cost and the good opportunities for integrating it with coal‐fired power plants . Calcium looping technology involves a reversible reaction between CaO and CO 2 .…”

“…In realistic industrial applications, calcium‐based sorbents are calcined under a high‐concentration CO 2 atmosphere at a temperature above 900°C in the calciner. The realistic calcination condition, like the severe calcination condition, aggravates the sintering of the sorbents, which results in a sharp decay in CO 2 capture capacity . Although the carbonation conversions of calcium‐based sorbents under severe calcination conditions are improved by steam in the carbonation, they still decay with the number of cycles due to the severe sintering of the sorbent.…”

Kinetic analysis about the CO2 capture capacity of lime mud from paper mill in calcium looping process

“…The reuse of the lime mud in environmentally friendly way and CO 2 capture from flue gas can be simultaneously realized if lime mud can be used as CO 2 sorbent in carbon capture system. Calcium looping process is widely considered as one of the most potential methods that can achieve deep CO 2 emission reduction in view of its advantages including low‐cost CO 2 sorbent 11 and proven CFB technology 12 . The CO 2 capture capacity of the calcium‐based sorbent can be further enhanced by synthesizing inert supported sorbent 13,14 and template‐assisted synthesis approach 15,16 .…”

“…Calcium looping process is widely considered as one of the most potential methods that can achieve deep CO 2 emission reduction in view of its advantages including low-cost CO 2 sorbent 11 and proven CFB technology. 12 The CO 2 capture capacity of the calcium-based sorbent can be further enhanced by synthesizing inert supported sorbent 13,14 and template-assisted synthesis approach. 15,16 Therefore, the cost of this technology can be further reduced.…”